PHILADELPHIA (CBS) — Now that the warm weather is here and folks are breaking out their barbecue grills, Philadelphia fire commissioner Lloyd Ayers is cautioning cooks to take a good look at those devices before lighting them up.

Ayers says that with propane grills, secure connections are key.

“Over the wintertime you sometimes have little animals, insects, things that ferret into the grill,” he warns. “Sometimes spiders spin webs that block some of the orifices that you want to connect your gas line to. So you have to make sure that all of those things are clean, clear, and ready to connect.”

For those using charcoal, Ayers advises positioning the grill at least ten feet away from any vent or opening, such as a window or door, to avoid sending carbon monoxide fumes into the house.

“And never, ever use charcoal and grill in an enclosed area,” he warns, “because you will be emitting carbon monoxide. We’ve had people who were overcome by that grilling activity.”

Also, Ayers adds, make sure all grills — propane or charcoal — are not too close to your house. Otherwise, you may singe or burn your siding.